DE2544040C2 - Process for the production of modified tetrafluoroethylene dispersion polymers - Google Patents

Description

F CF ₃

fVVf

CF-CF ₁ -O-

CF,

CF ₁

where η = 0 to 4. or a mixture of these perforated vinyl ethers is carried out as modifying agents.

2. The method according to claim 1, characterized in that the polymerization with a template customary aqueous seed dispersion, consisting of dispersion particles of polytetrafluoroethylene or one of at least 90% by weight tetrafluoroethylene units containing copolymers of tetrafluoroethylene and a fluoroolefinic compound, is carried out.

3. The method according to claim 1 and 2, characterized in that the modifying agent at The beginning of the polymerization is presented.

4. The method according to claim 1 and 2, characterized in that the modifying agent in the ongoing polymerization with a tetrafluoroethylene conversion of a maximum of 70% is fed back.

5. The method according to claim 1 and 2, characterized in that the modifying agent of The beginning of the polymerization up to a tetrafluoroethylene conversion of at most 70% continuously or is added in portions.

6. Use of the tetrafluoroethylene dispersion polymers prepared according to Claims 1 to 5 for processing into solid and hollow profiles according to the paste extrusion process.

It is known that polymers of Tetrafluoräthy- be obtained lens according to Two principally different methods köntien: Using the method of suspension polymerization coarse fV are lymerisate having an average particle size of about μ to about 1000 μ obtained which, after grinding or after drying and Treatment to improve the flowable wedge for press-sintered processing or the Rarrt ^ extrusion technique are suitable, after the process of dispersion polymerization, on the other hand, using suitable emulsifiers, stable aqueous polytetrafluoroethylene dispersions with a particle size of about 0.05 to 0.6 μ are obtained which are particularly suitable for impregnation and coating purposes. Free-flowing powders can be obtained by mechanical coagulation and subsequent drying of the precipitated dispersion polymer. These polytetrafluoroethylene powders obtained from the dispersion polymerization are, however, suitable for the so-called paste extrusion technique, in which the polymer is first coated with a liquid lubricant, e.g. B. a higher boiling hydrocarbon, made into a paste and then extruded through nozzles under pressure. This is noticeable in that due to the lack of orientability of the material, a rough surface of the extrudate and the formation of knots are observed. In order to achieve a uniform extrusion process and to eliminate the defects mentioned,

CF = CF ₂ must therefore be aimed at dispersions, in

which the dispersion particles approximate as closely as possible

(I) have a spherical shape. It is also necessary

the excessive extrusion pressure in paste extrusion of dispersion polymers by special measures during the polymerization to change to lower the polymer.

Processes have already been described which aim to improve the extrudability of the paste

to improve in dispersion polymers of tetrafluoroethylene. So is from US-PS 30 88 941 a Process known in which the dispersion polymerization of tetrafluoroethylene with a template Seed dispersion from the tetrafluoroethylene homopo-

r> Iymerisat takes place. The dispersion particles thus obtained however, have an undesirably broad grain size distribution. To eliminate this disadvantage is recommended according to US-PS 36 54 210 the use of a seed template, which consists of dispersion copolymers of

»Ι predominantly tetrafluoroethylene with chlorine, bromine, iodine or hydrogen-containing fluoroolefins. especially with trifluorochloroethylene. consists.

In both of these procedures, the Production of the seeds following the main polymerization

4> no modifying substances with a regulating effect or chain-breaking properties are used. This is / was in terms of the amount of polymerization Speed is an advantage, as modifying additives as a result of their regulating effect, a lowering of the

Vi space-time yield of polymer result However, the disadvantage of the processes mentioned without modification in the main polymerisation is that higher melting viscosity of the polymer thus produced ren as well as a reduced alternating flexural strength and

■ >> Transparency as well as an increased brittleness of extrudates made therefrom. For example, pipes or hoses When using a Seed template from (opolymer manufactured products there is also an increase in the ijjjn hrump

M) fes noticeable during sintering, which means, for example, at the manufacture of pipe linings the MaDhalug is unfavorable.

From US-PS 3142 665 a process ZUr production paste-extrudable dispersion polymer

sate known at least during the last Part of the polymerization of tetrafluoroethylene so-called modifiers, for example water * substance, methanol or a perfluoroalkene or a

Perfluoroalkoxyalkene, are present. The so produced Polymers and the paste extrudates produced therefrom do not only have good extrudability within a wide range of reduction ratios (this is the important one in paste extrusion Area ratio of preform cross-section to nozzle opening cross-section) also a reduced melt viscosity and increased transparency and flexural fatigue strength; however, like those of the above processes, these products also show one Number of disadvantages, especially with regard to its properties as an insulating material for electrical Ladder. In the case of thin-walled sheathing of wires, the electrical fault test results a relatively high number of electrical breakdowns, which can be traced back to imperfections, especially cracks, in the insulation. That number increases by a multiple or leads to the occurrence of permanent breakdowns if to higher reduction ratios is passed over during paste extrusion. Because such faulty places from the insulated conductors need to be cut out, this leads to a shortening of the defect-free wire length and to a high percentage of rejects. Furthermore, the number of electrical faults is increased when the so-called deduction ratio is increased. Below this should be the quotient of the cross-sectional area of the nozzle opening (minus cross-section of the metallic conductor) and the cross-sectional area of the unsintered insulation will. In practice, it is desirable to use higher values than possible for this drawdown ratio 1: 1, as this is an essential smoother surface and an improved gloss or Surface of the jacket can be achieved. State-of-the-art products however not only show a significant increase in the entire range of draw-off ratios electrical faults with a clearly increasing tendency with an increase in the reduction ratio. but it is also their somewhat favorable behavior with regard to these properties in relation to one very narrow processing area limited with regard to the deduction ratio. This forces the verar beiter, drive under conditions that are as constant as possible / u, which is extremely difficult in practice.

The decreased transparency of the using Products made from one seed template goes in many Cases up to a clouding of egg isolation (dem so-called lime effect), which is unpleasant, especially in the case of colored insulation, when the color is lightened makes noticeable.

The invention is based on the object Process / ur production of niodified tetra fluoroethylene dispersion polymer with good paste extrusion properties to create, with particular emphasis on improved suitability as Isolation <material for electrical, see I.eit «: r is laid

According to the invention, this object is achieved by a process for the preparation of modified tetrafluoroethylene dispersion polymers by polymerizing tetrafluoroethylene in aqueous dispersion in the presence of modifying agents, customary emulsifiers and customary additives under known conditions, which is characterized in that the polymerization of the tetrafluoroethyleneh in the presence of 0 , 0005 to 13% by weight, based on the tetrafluoroethylene used, without taking into account any seed dispersion which may be present, of a perforated vinyl ether of the formula F CF ₃

CF ₃

CF-CF ₃ -OI-CF = CF

CF ₃

where η = 0 to 4, or a mixture of these perfluorinated vinyl ethers is carried out as a modifying agent.

The production of the within the scope of the invention

ii ßetr process used as a modifier perforated vinyl ether of the formula I is carried out by reacting hexafluoropropene epoxide with a Phosphoric acid tris-dialkylamide of the formula

O

Il

(R) ₃ N -; ^j -N (R) ₃
N (R) ₂

Ο — 4-CF-CF ₂ -O-

in particular phosphoric acid tris-dimethylamide, too an acid fluoride of the formula

CF-C

I \

CF ₃ F

(III)

The acid fluorides of the formula III above are then hydrolyzed to the corresponding fluorine .vliuren Carbo ^, they are neutralized with alkali, and heating the obtained carboxylic acid salts at temperatures above 15O ⁰ C, while pyrolytically converted to the corresponding perforated vinyl ether of the formula I. The synthesis route for these perfluorinated vinyl ethers of the formula I is the subject of older German patent applications. Mixtures of such perfluorinated vinyl ethers of the formula I can also be used. Perfluorinated vinyl ethers of the formula I with η - 0 or I or mixtures of these compounds are preferably used as modifying agents.

The proportion of modifying agent which must be present during the dispersion polymerization is 0.005 to 1.5% by weight, preferably 0.01 to 1.0% by weight, based on the tetrafluoroethylene used (without Consideration of a possible seed supply), regardless of whether the dispersion polymerization with or is carried out without submission of a seed dispersion. The modifying agent is preferably in one Total amount metered into the reaction vessel before the start of the polymerization. However, it can also be used in the ongoing polymerization can be fed in at any point in time before a conversion of 70%, Preferably 40% is reached. Part of the required amount of modifying agent can also be used Presented and another part during the polymerization If necessary, the modifying agent can be added from the beginning of the

ongoing polymerization on continuously or in portions up to a tetrafluoroethylene conversion of 70%, preferably up to 40%.

The dispersion polymerization takes place under customary pressures of 5 to 30, preferably 8 to 16 atmospheres and temperatures of 10 to ^70.degree. C., preferably 20 to 40.degree. The dispersion polymerization takes place in the presence of the usual catalysts, redox systems being preferred, that is, combinations of a peroxidic compound such as an organic or inorganic peroxide, a peracid, a persulfate, perborate or percarbonate with a reducing component, such as. B. a bisulfite, thiosulfite, dithionite, hydrogen sulfite, sulfinate or a diimine supplying compound, such as azodicarboxylic acid and its salts or azodicarbonamide. Combinations of alkali or ammonium persulphate with alkali bisulphites are preferred. In any case, it is a condition that the catalyst used must be water-soluble, especially in the alkaline range.

Furthermore, the emulsifiers customary for the dispersion polymerization d'-S tetrafluoroethylene are used, such as. B. described in US-P ⁰ 25 59 752. Examples of which are the alkali and ammonium salts of longer-chain perfluorocarboxylic acids, ω-hydroperfluorocarboxylic acids. Chlorofluorocarboxylic acids, perfluoridicarboxylic acids and also perfluorosulfonic acids and perfluorophosphonic acids. Preferred emulsifiers in the context of the process according to the invention are the ammonium salts of perfluorooctanoic acid and oj-hydroperfluorooctanoic acid. The emulsifier used is possible sol ¹ having no telogenic properties. The dispersion polymerization can, however, optionally be carried out in the presence of smaller amounts (0.0001 to 0.01, preferably 0.005 to 0.01 wt. Propene. Chloroform, carbon tetrachloride or methanol. Furthermore, anticoagulants or dispersion stabilizers such as longer-chain paraffinic hydrocarbons, paraffin waxes or so-called white oils, which should be liquid under the conditions of the polymerization, can also be present during the polymerization. Cyclic dispersion stabilizers can also be used as dispersion stabilizers Such as dioxane or tetrahydrofuran, also polyoxalkylates or their esters, ... B. alkylphenol polyglycol ethers, for example nonylphenol polyglycol ethers or triisobulylphenol polyglycol ethers, but also polyglycol esters of fatty acids or polyoxalkylals of fetiamines. Stabilizing agents of this type are described in US Pat of DRPS 17 20 738. In addition, suitable dispersion stabilizers are polyalkylene glycols, such as, for example, diethylene, triethylene, dipropylene, tripropylene glycol and higher analogs and mixed glycols of ethylene and pmpylene oxide is up to a solids content of 10 to 40% by weight. preferably I 5 bi '. 30% by weight.

The above-described Dispersionspolymerisa tion of tetrafluoroethylene in the presence of the invention-Aings according to The modification mills used can be made without the addition of seeds. Preferably will however, a customary seed template of polytetrafluoroethylene or, particularly preferably, a customary seed template • from a copolymer of tetrafluoroethylene with a fluoroolefinic compound which is at least 90 Contains wt .-% tetrafluoroethylene units, vurgtgc ben.

The production of this Saatvoriage can according to the customary methods of the above described

ϊ Dispersion polymerisation of fluoroolefins with the the same above-mentioned catalysts, emulsifiers and take place at the same pressures and temperatures, but without the addition of the modifying agent. In the Production of a seed dispersion from polytetrafluoro-

"Ethylene is the stabilization of the dispersion by one the above stabilizers required, while in the preparation of a seed template from the mentioned copolymers a stabilizing agent can be present. Dispersion copolymerization for a copolymer seed takes place in principle in the same way. Of the fluoroolefinic compounds, which are used here as comonomers may be mentioned in particular:

, _n a) fluoroalkenes of the formula
RR

el)
e)

C = C

wherein

one of the radicals R = fluorine,
one or 2 of the radicals R = H, Br, CI or] are,
the remaining radical or the two remaining radicals R is or are fluorine, a perfluoroalkyl group or a perfluoroalkoxy group: the perforated alkyl or alkoxy groups mentioned have 1 to 4, preferably 1 to 2, carbon atoms in the branched or preferably straight chain: the perforated alkyl or alkoxy groups, if two radicals R consist thereof, can be identical or different within the specified limits.
Perfluoroalkene formulas

C F. = C

R,

R,

R- CF = CF-R,

or

C = CF-R,

where R, and R'r is a perforated alkyl radical with 1 to 4, preferably 1 to 2 carbon atoms (branched or preferably straight-chain), where R ' ₍ either the same as Rr or different therefrom' (preferably CFj),

Ferfluoro (alkyl vinyl ether of the formula CFj = CF = QRr, where Rr is a perforated Afkyifest with 1 to 5, preferably 1 to 3 carbon atoms (branched or preferably straight-chain).
perfluorinated vinyl ethers dec above formula I or
Perfluoro (2-inelhylen-4-me (hyl-1-3-dioxolane).

in

15th

Yo

In addition to the compounds mentioned under d) and e), of the comonomers of groups a), b) and c) the following are mentioned, for example:

1.2-difluoroethylene,

1.1- and I ^ -Dichlorodifluoräthylcn,

1.1- and 1.2-dibromodifluoroethylene,

1.1 and 1.2 diiododifluoroethylene,

i -Chlor-1 -bromodifluoroethylene,

l-chloro-2-bromodinuoräthyleni

Trifluorobromethylene, trifluoriodethylene,

! -Chlor-, 1-bromo- and I-iodine-2,2-difluoroä (liylen,

! ■ Chlorine, I-bromine and I-iodine-I.2 * difluoräthyleri.

IH-pentafluoropropene (I),

2H-pentafluoropropene- (1),

J.IH- and I.2H-tetrafluoropropene- (I),

I- and 2-chloropentafluoropropene- (l),

1- and 2-bromopentafluoropropene- (l),

l-iodine pentafluoropropene (l),

1.1- and l-2-chlorine or bromotetra-

fluoropropene- (l),

IH- and 2H-heptafluorobutene- (I),
1.1 H- and I.2H-hescafluorobutene- {1).
2H-heptafluorobutyn- (2).
lH-heptafluoroisobutene- (l),
1- and 2-chloroheptafluorobutene- (l).
I -chlorheptafluoroisobutene-i; I),
IH- and 1 -Chlornonafluorpenlen-ft),
Trifluoromethyl and pentafluoroethyl

I -fluoro 2.2-dichlorovinyl ether.
I-trifluoromethyl and I-tetrafluoroethyl

(2.2-difluorovinyl) ether.
Perfluorobutene-f I) and - (2). Perfluoroisobutene,
Fluoropentene- (1) and - (2).
Perfluoro [2-methylbutene- (1)], - [2-methyl- _J3

buten- (2)] and- [2-methylbutene- (3)], '
Perfluoro (methyl vinyl) -. Perfluoro- (ethylvinyl) -

Perfluoro- (butylvinyl) -. Perfluoro

(isopropylvinyl) and perfluoro-

(isobutyl vinyl) ether

In addition to the perfluoro (2methylene-4-methyl-iJ-dioxolane) already mentioned, the following are preferred comonomers: trifluoroethylene. Vinylidene fluoride. Perfluoropropene. Perfluoro (propyl vinyl) ethers and, as a particularly preferred comonomer, trifluorochloro ethylene. In a preferred manner, the perforated vinyl ethers of the formula I, in particular those with the index η = »0 or I. or mixtures of these perfluonated ethers, which are used as modifiers in the main polymerization, can be used in the formation of a copolymer resin template in a proportion of up to 10% by weight can be used as comonomers.

The proportion of the fluoroolefinic compounds as comonomers in the copolymer seed (based on the copolymer as solid) should be 0.1 to 10% by weight. preferably OJ to 5% by weight. be. The remaining part, supplemented around 100%. consists of units of tetrafluoroethylene. In principle, it is also possible to use two or more of the fluoroolefinic compounds mentioned in a mixture as comonomers. The amount of tetrafluoroethylene used in the seed polymerization is such that the seed dispersions obtained have a solids content of 3 to 15%, preferably 5 to 12% by weight. exhibit. fv>

The transition point of the crystalline phase of the solid such Copoiymerensaat is 290-322 ° C preferably at 300-317 ° C This Saatdispersionen contain predominantly spherically shaped, uniformly sized dispersion particles with an average diameter of O ₁ Ol to 0.2, preferably 0, 03 to 0.15μ.

The seed template described in this way is optionally used in the polymerization according to the invention Process presented, in such an amount that the seed solid in the solid of the later Total dispersion polymer is contained in a proportion of 0.5 to 15, preferably 4 to 12% by weight. The seed can be presented in such a way that the aqueous seed dispersion together with the aqueous Solution of the catalyst and the other auxiliaries required for the polymerization in the reaction vessel is presented, also the modifying agent either presented or in the one described above Way, and the required amount of gaseous tetrafluoroethylene is injected into the reactor. However, it is also possible to use the quantities of catalyst and the rest necessary for the polymerization To submit auxiliary materials already during the seed polymerization, after the end of the dispersion polymerization Seed to undertake a short intermediate relaxation and then the main polymerization with the addition of Tetrafluoroethylene and the modifier to continue.

Both the dispersion polymerisation of the seed stock Like that of the polymerization process according to the invention, it should preferably be neutral in the alkaline environment Medium, d. H. at pH values of approx. 5 to approx. 8, preferably 5 to 7. Be used for this purpose alkaline agents such as sodium or potassium hydroxide, preferably aqueous ammonia solution, are added to the liquor, fed.

The modified polytetrafluoro obtained in this way by the process according to the invention Ethylene dispersions can be coagulated according to the customary and known processes. This can done by mechanical coagulation. for example with the help of a fast-running stirrer or by spraying under pressure, and the dispersions can also be prepared, for example, by adding acids or electrolvten fail. The moist powder obtained in this way is dried at temperatures from approx. 30 to approx. 200 ° C. preferably 50 to 180 ° C. in stationary or in convection drying cabinets. Achieving the lowest possible extrusion pressure in paste extrusion is favored if the drying at low temperatures of about 40 to about 80 ° C is carried out according to the so-called fluidized bed technique.

The increase in the process according to the invention Products show a number of surprisingly improved properties. In Table I is shown that they are both at low and high reduction ratios in terms of the number of electrical defects (breakdowns per 1000 m length of the insulated conductor) as well as with regard to the Transparency are clearly superior to insulation. It should be noted that the comparison products at the increased reduction ratio of 2400: 1 are practically useless. Table II also shows that the processing latitude in terms of the draw ratio is considerably improved US-PS 31 42 665 produced product practically only in a very small range of the take-off ratio Giving satisfactory results is the number of electrical defects in the invention

yeast product within the entire range reduced to the optimum. The quality of the transparency is less with higher deduction ratios changes. Som * l can also do that in general

10

An increase in the haul-off ratio resulted in an improvement in the surface gloss and surface smoothness be better exploited.

Table I.

Often wedge and transparency of sheathed conductors with various redukliorisvefliältnisse

product Reduction 1 \ bzugs- Extrusions * Durchschliigii / 10000 m Transpa relative 1 whiill- Pressure, renz of RVM I. iis * M iltÜ insulation E.g. If *. Tab III of the I45D 1 1.27 550 0 I. according to the invention Procedure 2400 1 1.275 770 3 I- Ex. 28. 1450 I. 1.27 570 0 I. Tab. Ill 2400 1 1,275 790 4th 1 - Heisi »II from 1450 I. 1.27 650 52 4th U.S. 3,088,041 2400 I. 1,275 720 Permanent impact 4-5 Example 27 of 1450 I. 1.27 650 8th 3 US 36 54 210 2400 , 275 800 Continuous breakthrough 4-5 Ueisp. 17 of 1450 .27 560 10 I. US 31 42 665 2400 .275 770 62 1-2

The nozzle diameter with the reductin ratio 1450 1 i.4? .um, at the Rcdutlionsverliällnis 2400: I 1.244 mm. The reduction ratio in the extrusion of sheathed electrical conductors is understood as the area ratio

Preamble cross-sectional area

Nozzle opening cross-sectional area - conductor cross-sectional area

The withdrawal ratio is defined as the quotient of the cross-sectional area of the nozzle and the unsinhered insulation. When calculating the nozzle opening area, the cross-section area of the conductor is deducted.

The extrusion of electrical conductors was carried out with a Jennings wire extruder, model CEB 233-05. A seven-core silver-plated copper wire (silver plating 2 μ) was used after the AWG standard No. 22 (= American Wire Gauge) with a total conductor diameter of 0.76 mm. Shell special gasoline was used as a lubricant, Boiling range 100 to 125 ° C, used.

of 15 m / min, the extrusion speed of the Polymer is reduced by reducing the piston advance rate (see Table II). The increase in the extraction ratio has a reduction in the thickness of the insulating layer and thus a Reduction of the cable diameter result. The value for the deduction ratio results from the Quotient of the cross-sectional area of the nozzle opening

The mixture with the modified PTFE dispersion polymer was 18% by weight. The preform made of polymer and lubricant, which is pre-compressed at a pressure of 100 bar, is fed into the pressure cylinder of the wire extruder, the conductor is guided through the drilled mandrel, the wire guide and the nozzle.The wire then runs over a drying distance of 4 m as well as to extract the lubricant finally a sintering distance of 6 m in length, of about 280 ⁰ C to 450 ⁰ C ascending arranged temperatures to a trigger device, wherein the ABzügSgcschwihdigkeh varies Can be. An increase in the draw-off ratio is brought about by the fact that while the wire speed remains the same, toilA »*. Oii

Insulation. After the pull-off device, the insulated conductor continues to run through the electrical fault locator to the unwinder. A commercially available breakdown tester was used as the electrical fault locator used. The test was carried out at a test voltage of 3.5 kV (according to VDE measurement specification 0472) and a frequency of 100 Hertz. It became the number of electrical breakdowns per 1000 m length of the sheathed conductor registered. The strength of the sintered insulation for the type shown in Table I. The selected withdrawal ratio was 250 μ, accordingly "a diameter of the sintered, insulated conductor of 1.26 mm.

Table II Deduction delay
ratio Number of copies
per 1000 m transparency
the insulation Product made by 1.0
1.08
1.12
1.27 0
1
0
0 1
1
1
1 Example 16, Tab. III
de «erfinrinnpKgggestgn
Procedure

25 44 040 12th Tfiirisp'iifori / 2 -2 2 - 2 the insulation -2 - 2-3 I ίΐ -2 1-2 1 cont
I. \ hmgsvef / alii of the punches -l - 1 -3 k I'focJukl hcfgcslclll to / iiillnis per KXk) ni 1 ' , 30 0 1-2 I Example 16, Tab. Ill , 33 0 -2 I of the founding guideline , 35 I. -2 1 procedure , 38 0 1 .42 0 , 4.1 I. \ , 0 0 I Example 28 _t Tab. Ill , 08 I. .12 '&
P. , 27 I. , 30 ( Jl
. », , 33 , 38 I. , Ii P. , 43 I. ,1 i; US 31 42 665, example 17 .15 I. .17 ) If , 19th 1 ί
ι .22 1 .25 I. , 27 .30 .32 3 \ ii 5 , 36 6th , 42 I. 4th 2 15th 12th 16 17th Continuous breakthrough Oauer penetration

The reduction ratio was 1450: 1 in rough cases (Nozzle diameter 1.47 mm), the wire speed was 15 in / minute.

The quality of the transparency of the insulation obtained is visualized in Tables I, II and IV rated according to the following scale:

Hotel:

Isolation completely clear. Metallic conductor in original color, translucent.

Grade 2:

Isolation slightly tarnished. Original color of the metallic conductor no longer recognizable.

Note 3:

Insulation shows partially covered areas. Metallic conductor still visually recognizable. Generally increased opacity.

Grade 4:

Over 50% of the insulation when covered. Metallic conductor only partially recognizable.

Grade 5:

Insulation almost completely covered. Metallic conductor no longer recognizable.

The products produced by the process according to the invention can be made using Lubricants can also be processed into other types of profiles using paste extrusion, For example, to pipes, pipe linings, hoses, etc.After suctioning off the lubricant such profiles are sintered in the usual way. Another type of processing is the extrusion of unsintered Strands, soft with the help of, for example, a calender mill to form unsintered strips can be rolled out. These tapes can be further drawn to achieve lowered densities

■ κι and then by extraction, for example with Chlorinated hydrocarbons, to be freed from the lubricant. You can find a sealant in Armature /, or for nsdi d-Γ Wickdischnik i ^ absusol solutions Use. By sintering such products in

• In a fixed state, highly porous membranes can be used getting produced.

The modified tetrafluoroethylene dispersion polymers prepared according to the invention can be used for Improve their mechanical properties or

thus, if necessary, they can also be mixed with conventional fillers to reduce the frictional resistance. ; The mixing in of fillers can be done in the dispersion state as well as in the coagulated powder state take place. Up to 50% by weight, based on the total mixture, filler can be added, preferably 5 to 30% by weight. All kinds of non-metallic and metallic, granular and fibrous Fillers are suitable. Examples include: fiberglass. Asbestos, mica, graphite, soot, silicon dioxide, but also powdered metals such as copper, Aluminum, silver, or alloys such as bronze or brass. Furthermore, the products of the invention Process also with other known auxiliaries, such as inorganic or organic pigments or dyes, optical brighteners and the like are provided, as far as these are stable at the sintering temperature or use is provided in the unsintered state

The products filled in this way can be used to manufacture the above-mentioned profiles such as pipes, hoses, tapes and the like., For example for Bowden cables, can be used. Fillers, e.g. B. bismuth oxide, increase the X-ray contrast in the manufacture of medical Catheter tubes. The modified polytetrafluoroethylene dispersion polymers obtained according to the invention are also produced in the form of their aqueous dispersions, if necessary after concentration, for coating metallic surfaces or for impregnating porous ones Use bodies such as fiberglass or textile materials.

The examples in Table III (No. 1 to 27) are intended to Explain the production of the products by the process according to the invention. In Tables IV and V are also ^ Other properties with regard to electrical defects, transparency and for extra-deep hoses are given.

At the PoWmerisstlon ^ ernäö Tsbeüc !!! will In principle, proceed as follows:

1st hall level

The polymerization autoclave with a capacity of 4001 is enamelled and equipped with an anchor stirrer. After presenting the liquor, the • us 2101 deionized water, 5.3 cm ^{3 of} 2% strength by weight Rupfer (II) sulfate solution and the amounts of emulsifier (NH ₄ salt of perfluorooctanoic acid) and Ammonia solution (in all cases 18% by weight solution in water), the amounts of comonomers listed in Table III, column 2 (except Examples 26 and 27, pure polytetrafluoroethylene seeds) are added in gaseous form after repeated nitrogen purging against a constant stream of tetrafluoroethylene. Thereafter, the pressure is increased to (4 atmospheres) by adding tetrafluoroethylene and the polymerization is started by adding 8 g of sodium hydrogen sulfite and 7.7 g of ammonium persulfate in aqueous solutions with stirring .-%.

2. Main polymerization

id In a 400 l polymerization autoclave wiro c ^: ne liquor, which consists of 2101 deionized water. 184 g NH ₄ salt of perfluorooctanoic acid. 252 cm ^{3 of} ammonia (18% by weight in water), 5.3 cm ^{3 of} copper (H) sulfate solution (2% by weight) and those in Table III, column 3

1-3 specified additives is submitted. Seed dispersion is to be understood as meaning the seed stage produced in accordance with the corresponding line in column 2 (fat content 10% by weight).
After repeated nitrogen purging is ^u by supplying Tetrsf'uoräih! Cn the pressure SIIF 14 äiü increased and simultaneously metered quantity of perfluorinated vinyl ether of the formula I as indicated in Table III, column 3;. The liquor is heated to 28 ° C. and the polymerization is carried out by metering in 9.5 g

2ΐ sodium hydrogen sulfite and 14.7 g ammonium persulfate started in aqueous solutions with stirring. Polymerization takes place up to a solids content of 20% by weight.

3. Work-up

jo In an enamelled with MIG-RührerundSlromstörer equipped boiler, the resultant dispersion at 10 percent is .- diluted% solids and stirred at a temperature of 20 "C. After three wash with 150! deionized water, the powder for 20 hours at 110 ⁰ C dried

Table III Hall level CF, = CFCl I lauplpolymerisationsstufe Seed dispersion Example no. CFs (CF,) "COONII ₄ (in the autoclave additionally Verb. 1 (;; - 0) Nlli solution 31.5 kg Ethylene glycol 1 (in the autoclave additionally CF, = CFCI 6.68 g Seed dispersion 750 g CF, (CF,),. COONII ₄ 4.2 g Verb. I (n - 0) 152 g NIl B solution 31.5 ka Diiithylene Glycol 2 96 cm ' CF, = CFCI 27.8 e Seed dispersion 750 g CFs (CF ^ XOONII ₄ 4.2 g Verb. Kn-O) 152 g N H B solution 47.3 kg Diethylene glycol 3 96 cm ' CF .. - CFCI 77.5 g Seed dispersion 750 g CFs (CF ^) XOONI I ₄ 4.2 g Verb. I (n = 0) 152 g NHs solution 44.0 kg Diethylene glycol 4th 96 cm ' CF. - CFCl 83.4 e. Seed dispersion 750 g CF -. (CF.) "COONII ₄ 4.2 g Verb. I (n = 0) 152 g NH! Solution 37.8 ka Diiithylene Glycol 5 96 cm ' CF, = CFCi 139 a Seed dispersion 750 s CF. (CF _{:) h} COONH ₄ 4.2 g Verb. Hn = Q) 152 g NIH solution 473 kg Diethylene glycol 6th 96 cm ' CF, = CFCI 155 a Seed dispersion 750 g CF-TF.i.rnrvNiTi. 4.2 g Verb. Kn-O) 152 g NHs solution 37.8 kg Diethylene glycol 7th 96 cm " 166.8 a 750 g 0.42 e ! 52 g 96 cm '

A A

15th

040

Fortxei / ung

Example no. Seed pillar

(additionally presented in the autoclave, see text)

750 g 152 g 96 cm '

750 g 152 g 96 cm '

750 g 152 g 96 cm '

750 g 152 g 96 cm '

75 (lg 152 g

% cm 75Og 152 g

96 cm ¹

75Og 152 g

96 cm '75Og 152 g

9h cm '

232 g 184 g 116 cm ¹

15 (lg 184 g lld cm '

15 (1 g 184 g 116 cm '

150 g 184 g 116 cm '

150 g 184 g 116 cm '

15 (Ig 184 g 116 cm '

150 g 184 g 116 cm '

45Og 184 g 116 cm '

350 g 184 g 116 cm ¹

150 g 184 g! 16 cm '

184 g 116 cm * 4.2 g

CF, = CFCI CF ₁ (CFj) ₆ COONH ₄ NH., Solution CF, == CFCI CF ₅ (CFj) ₆ COONH ₄ NH! Solution

CF, = CFCI CF ₅ (CFj) ₆ COONH ₄ NFl! Solution

CF, = CFCI

CF ₅ (CFj) ₆ COONH ₄

NII _; -Solution

CF; - CFCI

NHi solution CF. = CFCI CF ₁ (CF-UOONH ₄ N H. solution

CF, - CFC!

₁ (CrU ₄ NH solution

CF- - CFCI

CFi (CF;),. COONH ₄

NII; solution

CF. CFCI CF ₁ (CF. (, COONI Ij Nl I, solution

(F CFCI CF ₁ (CF. (, COONH, NiII

CF. - CFCI CF ₁ (CFO ₁ XOONH ₄ Nile solution

CF. CFCI CF ₁ (CF-UOONH, Nile solution

CF. CFCl CF ₁ (CF-UOONH, Nil. Solution

CF. - C FC I CF ₁ (CF-I ₁ XOONH ₁ NH. Solution

CF, CFCI CF, (CF.), XOONII,

N Hi solution

CF ₁ (CF-J.OCF CF CF ₁ (CF.UOONII ₄ NII; solution

Verb. I (/; O)

Cf ₁ (CFUOONII ₁

NII ₅ solving

CF, = CH, CF ₅ (CFj) ₆ COONII ₄ NH s solution

CF ₁ (CF ₁ UOONH ₁

NII ₁ -LuSUiIg

Dioxin! main polymerisation column (in the autoclave / otherwise presented, see text)

18.85 kg G kg kg Seed dispersion 130 239/237 166.8 0.42 g Verb. I (n = O) 37.8 kg kg Diethylene glycol 166 g Seed dispersion 37.8 G G Verb. 1 (w = 0) 278 g kg kg Hall dispersion 4.2 Verb. I (λ = O) 37.8 G B. Diethylene glycol 556 g kg kg Seed dispersion 4.2 G Verb. I (n = O) 37.8 > g Diethylene glycol 77 ° kg kg Seed dispersion 43 G Verb. I {n - O) 44.1 G G Diethylene glycol 77.8 kg kg Seed dispersion 4.2 Verb. I (n = O) 44.1 e, G Diethylene glycol 100 e kg kg Seed dispersion 4.2 Verb. I (/; O) 44.1 G G Diethylene glycol 155 g kg kg Seed dispersion 4.2 Verb I (λ = O) 44.1 G G Diethylene glycol 155 g kg kg Seed dispersion 2.1 Verb. I («= 0) 44.1 1.05 g G Diethylene glycol IlOg 44.1 Seed dispersion 55 g Verb. I (/ ϊ 0) 44.1 Diethylene glycol 55 g Hall dispersion 2.1 Verb. I (/; - 0) 44.1 Hall dispersion HOg Verb. I (/; - 0) 2.1 Diethylnglycol 37.8 Seed dispersion 55 g Verb 1 (n = 0) 1.0! Diethylene glycol 44.1 Hall dispersion 155 g Verb I («0) 2.1 Diethylene glycol 44.1 Seed dispersion 155 g Verb. I (it - 0) 2.1 Diethylene glycol 37.8 Seed dispersion IlOg Verb. I (; / - 0) 2.1 Diethylene glycol 31.5 Seed dispersion 155 g Verb I (// 0) 2.1 Diethylene glycol 44.1 Hall dispersion 155 g Verb. I («= 0) 2.1 Diethylnglycol Seed dispersion Verb. I (n = 0) Diethylene glycol

continuation

Example no. Seed pillar

(additionally presented in the autoclave, see text)

I main polymerization column (additionally presented in the autoclave, see text)

184 g 116 cm 4.2 g

232 g 184 g

³ NHr solution dioxane

CF, = CFCI CF ₃ (CFi) ₆ COONH ₄

116 cm 'NH _r solution

37.8 kg
100 g
2.1 g
44.1 kg
155 g
2.1g

Seed dispersion verb. I (n = 0) diethylene glycol

Seed dispersion verb. I (n = 3) diethylene glycol

Table IV

Further extrusion results from wire extrusion

example Extrusion transparency Electric No. pressure Carbon copies / (bar) 1000 m 1 580 I- 3 2 575 1- 4th 3 (.35 1- 2 5 blO 1- 1 6th 565 1- 2 IO 580 1-2 2 11th 600 1 2 13th 530 I. 0 15th 560 I- 2 16 550 1 0 28 570 I. 0

Reduction ratio 1450: I, nozzle diameter 1.47 mm, draw ratio 1.27.

Table V

Test results of the hose extrusion I Hose measurement outside: 14.6 mm 0; inside: 13.3 mm 0; Reduction ratio 90: I)

example Tear resistance *) Elongation at break *) across No. (kp / cm ² ) (%) 610 along across along 620 3 36.4 28.6 340 600 6th 29.3 26.4 300 600 16 31.4 27.1 370 28 36.0 28.5 335

·) Determined according to ASTM D 1457-69T.

Claims (1)

Patent claims: 1. Process for the preparation of modified tetrafluoroethylene dispersion polymers by Polymerization of tetrafluoroethylene in aqueous dispersion in the presence of modifying agents, customary emulsifiers and customary additives under conditions known per se, d a through characterized in that the polymerization of tetrafluoroethylene in the presence of 0.0005 up to 1.5% by weight, based on the tetrafluoroethylene used, without taking into account any existing seed dispersion, a perfluorinated vinyl ether of the formula